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Ear

Organs of Corti, seen through a powerful microscope, showing hair-like endings (in yellow) projecting from sensors. Your ears detect sounds, so allowing you to hear. Sound waves are created by a vibrating source, such as a plucked guitar string. These sound waves are channelled into the ear and transmitted to its innermost part, the cochlea. Here sound vibrations are turned into nerve signals and sent to the brain where the sounds are actually "heard" and interpreted. The ears also send information to the brain that helps you balance.



How the ear works

The delicate working parts of the ear are behind the ear flap, or pinna. They are encased and protected within the skull bone.
The three tiny ear bones, or ossicles, are the smallest bones in the body.The flap on the side of the head that we call the ear, is simply its outermost part. Called the pinna, this flap of skin and cartilage funnels channels sound waves in the outer ear canal. At the end of this canal, sound waves hit the eardrum, a taut piece of skin, and make it vibrate. These vibrations are transmitted and amplified by three tiny bones linked together: the hammer (malleus), anvil (incus) and stirrup (stapes). These are known as the ossicles. In-and-out movements of the stirrup transmits the vibrations into the fluid-filled inner ear where the snail-shaped cochlea is located.
Cross-section through the cochlea

Inside the cochlea

Decibels (db) are a measure of sound. The softest sounds that are audible are 10 db. Talking normally is 60, shouting 90 and a very loud scream is 120—louder than a road drill (115).

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